Diprotonated Hydrogen Halides (H3X2+) and Gitonic Protio Methyl- and Dimethylhalonium Dications (CH3XH22+ and (CH3)2XH2+):  Theoretical and Hydrogen−Deuterium Exchange Studies1

Oláh, George A.; Rasul, Golam; Hachoumy, Mohammed; Burrichter, and Arwed; Prakash, G. K. Surya

doi:10.1021/ja994044n

Cited by 26 publications

(24 citation statements)

References 23 publications

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“…The earlier calculations by B3LYP/6-31G(d,p) and B3LYP/6-31+G(d,p) methods of di-and trialkylhalogen cations [2,3] have shown that they possess an angular structure, and the positive charge on the halogen atom grows in a series F, Cl, Br, I in the full agreement with the decrease in their electronegativity.…”

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confidence: 72%

Quantum-chemical simulation of boron- and halogen-containing polymers

Gapurenko

Minyaev

2011

Russ J Org Chem

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Quantum-chemical method of density functional theory B3LYP/6-311+G(d,p) was used to study the energy and structural characteristics of boron-and halogen-containing condensation polymers C n+2 H n+4 B 2n X n (X = F, Cl, Br; n = 1, 2, ...), constructed based on 1,2,6-halodiborenes. All possible condensation versions were analyzed and the structure of the most stable polymer was established. It was shown by AIM-analysis that in the systems under consideration bicoordinated halogen atoms were present.Halogen atoms at bonding with two or more atoms exhibit a hypercoordination owing to the formation of nonclassic multicenter bonds, e.g., in dialkylhalogen ions that are good alkylating agents [1]. The earlier calculations by B3LYP/6-31G(d,p) and B3LYP/6-31+G(d,p) methods of di-and trialkylhalogen cations [2, 3] have shown that they possess an angular structure, and the positive charge on the halogen atom grows in a series F, Cl, Br, I in the full agreement with the decrease in their electronegativity.At the same time the bicoordination and moreover the hypercoordination of halogen atoms in the electrically neutral compounds up till now has not been experimentally detected. We formerly calculated [B3LYP/6-311+G(d,p)] the molecular structure of heteroanalogs of benzene and pyrrole (fl uorol and fl uorabenzene) and also isoelectronic to them boron-substituted derivatives containing bicoordinated fl uorine atoms, and their stability was demonstrated [4]. Among the various stable isomers of halodiborenes the most energy feasible is isomer I containing the boron atoms in the ortho-position with respect to the halogen [4]. The next stable isomer, 1,2,4-halodiborene, is by 42.7, 34.4, 31.7 kcal mol −1 (for X = F, Cl, Br respectively) less energy favorable than isomer I (without accounting for the zero harmonic oscillations ZPE). The last isomers are still less energy feasible.In this study by applying the calculations by density functional method B3LYP/6-311+G(d,p) the possibility was examined of designing stable neutral polymers C n+2 H n+4 B 2n X n (X = F, Cl, Br) from the simplest blocks of 1,2,6-halodiborenes I containing bicoordinated halogen atoms.HB BH X I, C 2v Quantum-chemical calculations by the method of density functional theory (DFT) [5] with the triparametric potential B3LYP in a valence-split basis 6-311+G(d,p) were carried out using the program package GAUSS-IAN-03 [6]. The identifi cation of all stationary points was performed by calculation of the Hesse matrix. The topologic AIM (atoms in molecules) analysis of the distribution of the total electron density by Bader method [7-10] was carried out applying an original program package AIMPAC [11]. For the estimation of the exchange interaction constant J we used the broken symmetry procedure for systems with unpaired electrons along the scheme developed in [12].We formerly showed [4] the stability of monocyclic neutral compounds with the bicoordinated fl uorine atom, but the character of the F-B bonds and the aromaticity of the ring were not investigated. The cal...

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confidence: 72%

Quantum-chemical simulation of boron- and halogen-containing polymers

Gapurenko

Minyaev

2011

Russ J Org Chem

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“…Most of the halonium ions except for fluor has been prepared as stable dialkyl chloro-, bromo-, and iodohalonium ions as long-lived ions. Theoretically, it has been calculated for (CH 3 ) 2 X + that the C-C distances are 2.66Å (X = F), 2.94Å (X = Cl), 3.10Å (X = Br), and 3.33 Å (X = I) and the corresponding CXC angels are 120.2˚ (X = F), 105.0˚ (X = Cl), 101.4˚ (X = Br), and 97.7˚ (X = I) [20] [21]. In excellent correspondence with these results is the recent chemical and theoretical evidence for a symmetrical fluoronium ion in solution [22].…”

Section: Hydrogen and Fluor Transitions As Divalent Atoms In A Three-mentioning

confidence: 99%

Three-Center Configuration with Four,Three, and Two Electrons for Carbon,Boron, Hydrogen, and Halogen Exchange. A Model and Theoretical Study with Experimental Evidence

Buck¹

2014

OJPC

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The introduction of specific sites in organic frames for accommodation of various modes of bonding has been focused on reaction types which are described by using different theoretical models with or without a definite experimental proof. In this study three-center four-, three-, and twoelectron systems based on carbon-, boron-, hydrogen-, and halogen exchange are under consideration. Based on the number of electrons in the transition state or transition complex it is shown that all transfer or exchange reactions share the same ratio numbers expressed as the quotient of the transitional bond distance under investigation and its normal bond length. With X-ray data of model systems it was even possible to give the ratio numbers for a three-center four-electron configuration experimental support with additional ab initio data. Furthermore a novel model type of substitution in organic chemistry is introduced through electrophilic insertion, informative for enzyme-substrate interactions based on the lock-and-key model. Reactions based on a three-center two-electron configuration mostly follow a nonlinear transition. In this alignment there will be a pursuit of cyclization for stabilization via homoaromaticity as homocyclopropenyl cation. The molecular dynamics of such a process is discussed based on recent X-ray crystallographic data of the symmetrically bridged, nonclassical geometry of the 2-norbornyl cation. In the present paper the focus is aimed at the transition intermediate of the (classical) 2-norbornyl cation involved in the isomerization into the nonclassical geometry. This model description is compared with a simple molecular rearrangement of the 1-propyl cation into the corner-protonated cyclopropane using the ab initio data. The exclusivity of the former isomerization compared with the latter one could be unambiguously demonstrated by the invention that the intramolecular electron shift can be expressed in a linear relationship between the concerned electron-donating and accepting H. M. Buck 34 bond lengths. Finally, the fluor transitions as divalent atoms in a three-center two-electron configuration are described. The role of fluor in comparison with the other halogens is striking. The attention was focused on an excellent correspondence between the recent chemical and theoretical evidence for a symmetrical fluoronium ion in solution. Simple dialkylfluoroniumions in contrast to the other halonium ions are not present in solution. Although the geometry of the fluoronium ion theoretically can be described as a real minimum, the C-F-C angle of 120˚ is apparently the borderline transition for dissociation in C + and F-C.

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“…This reaction involves hydridohalonium ions 126 as intermediates that subsequently undergo nucleophilic attack by excess alkyl halide. Protonation of methylhalonium ions to form diprotonated dications CH 3 XH 2 2þ have been calculated (B3LYP/6-31-G** level) 348 to occur primarily on the CÀH bond to form a pentacoordinated carbon with 2e-3c bond. 349 These hydridohalonium ions have been characterized by 13 C NMR spectroscopy.…”

Section: Acyclic (Open-chain) Halonium Ionsmentioning

confidence: 99%

“…Olah, Rasul, Prakash, and co-workers 348 have calculated the structure and stability of protonated dimethylhalonium dications (CH 3 ) 2 XH 2þ (B3LYP/6-31-G** level). Dialkyl alkylenedichloronium ions have not yet been directly observed.…”

mentioning

confidence: 99%

“…930 The infinite chains of the Te 7 2þ polycation in Te 7 2þ (AsF 6 À ) 2 consist of six-membered rings of chair conformation connected through Te atoms bridging between the Te(1) and Te(4) atoms (348). 930 The infinite chains of the Te 7 2þ polycation in Te 7 2þ (AsF 6 À ) 2 consist of six-membered rings of chair conformation connected through Te atoms bridging between the Te(1) and Te(4) atoms (348).…”

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confidence: 99%

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